BoilerFaultCodes 1 01
Overheat
Ariston Clas ONE System Fault codes & diagnostics
46 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
System Natural Gas 2020-present
GC Numbers 41-116-4941-116-5041-116-51
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Severity at a glance
Each cell = one fault code. Hover to identify. 3 High
4 Medium
39 Unrated
Just want the most common Ariston Clas ONE System faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes
All 46 documented codes
Tap any card for details
1 03
Insufficient circulation
1 04
Insufficient circulation
1 05
Insufficient circulation
1 06
Insufficient circulation
1 07
Insufficient circulation
1 08
Insufficient water (request filling)
1 09
System pressure > 3 bar
1 10
C.H. Flow temp. probe circuit open / short circuit
1 12
C.H. Return temp. probe circuit open / short circuit
Showing 11–20 of 46
1 14
External sensor circuit open / short circuit
1 16
floor thermostat contact open
1 18
Heating delivery probe problem
1 P1
Insufficient circulation indication
1 P2
Insufficient circulation indication
1 P3
Insufficient circulation indication
1 P4
Insufficient circulation indication
2 05
DHW In Probe Open Circuit (Solare temp. probe)
3 01
EEPROM error
3 02
Comunication error
Showing 21–30 of 46
3 03
Main P.C.B. error
3 04
Too many (> 5) resets in 15 minutes
3 05 Your boiler's internal computer has encountered a critical error and is unable to communicate with its own internal systems to function correctly.
Your boiler's internal computer has encountered a critical error and is unable to communicate with its own internal systems to function correctly.
Parts commonly replaced
- Main PCB
- Wiring harness
Related codes
3 06 Your boiler's internal computer is experiencing a communication error and cannot operate, meaning you currently have no heating or hot water.
Your boiler's internal computer is experiencing a communication error and cannot operate, meaning you currently have no heating or hot water.
Parts commonly replaced
- Main Printed Circuit Board (PCB)
- Wiring harness
Related codes
3 07
Main P.C.B. error
3 P9
Sched.Maintanace-Call Service
4 11
Room sensor circuit open or short circuit Zone 1
4 12
Room sensor circuit open or short circuit Zone 2
4 13
Room sensor circuit open or short circuit Zone 3
5 01
No flame detected
Showing 31–40 of 46
5 02
Flame detected with gas valve closed
5 04
Flame lift
5 P1
1st Ignition Failed
5 P2
2nd Ignition Failed
5 P3
Flame cut-off
6 10 Your boiler has detected that the internal water temperature has become dangerously high and has safely shut itself down to prevent damage.
Your boiler has detected that the internal water temperature has become dangerously high and has safely shut itself down to prevent damage.
Parts commonly replaced
- NTC temperature sensor
- Circulation pump
- Heat exchanger
- Main PCB
Related codes
6 12
Insufficient fan speed
7 01
Zone 1 send sensor defective
7 02
Zone 2 send sensor defective
7 03
Zone 3 send sensor defective
Showing 41–46 of 46
7 11 Your boiler is struggling to accurately read the temperature of the water returning from your heating system, which means it cannot heat your home efficiently.
Your boiler is struggling to accurately read the temperature of the water returning from your heating system, which means it cannot heat your home efficiently.
Parts commonly replaced
- Return temperature sensor
- Wiring harness
Related codes
7 12 Your boiler is having trouble communicating with the temperature sensor for your secondary heating zone, which may prevent that part of your home from heating up properly.
Your boiler is having trouble communicating with the temperature sensor for your secondary heating zone, which may prevent that part of your home from heating up properly.
Parts commonly replaced
- Return NTC sensor
- Wiring harness
Related codes
7 13 Your boiler is having trouble reading the water temperature in one of your heating zones, which may stop that specific area of your home from heating up correctly.
Your boiler is having trouble reading the water temperature in one of your heating zones, which may stop that specific area of your home from heating up correctly.
Parts commonly replaced
- NTC return sensor
- Wiring harness
Related codes
7 22
Zone 2 overheating
7 23 Your boiler has detected that the water temperature in one of your heating zones is higher than it should be for safe operation.
Your boiler has detected that the water temperature in one of your heating zones is higher than it should be for safe operation.
Parts commonly replaced
- NTC Temperature sensor
- Zone valve actuator
- Main PCB
Related codes
7 50
All Heating Zones locked
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